No little difficulty is experienced in settling the species of the Capuchins, for their fur is rather variable in tint, and some individuals differing so greatly as to cause them to look like another species. The general color of the Capuchin--_Cebus apella_--is a golden olive, a white fur bordering the face in some, though not in all individuals. _Cebus fatuellus_, commonly called the Horned Sapajou or Capuchin, is much more conspicuous than the last, as the erect fringe of hair that projects so prominently from the forehead indicates it at once: hence from the front, the hair assumes the appearance of two tufts or horns, from which peculiarity the animal derives its name. These horns are not completely developed until the monkey has attained maturity. There is also a manifest difference in color of hair, the Sapajou having a constant tinge of red in its fur. It is usually of a deep brown color, but in some individuals there is a marked resemblance to that peculiar purple-black which is obtainable by diluting common black ink with water, while in others the ruddy hue is so pronounced as to impart a chestnut tint to the animal’s hair. The fringed crest is tipped with gray. Perhaps no more interesting form of the Capuchins exists than the Weeper Monkey, or Sai, or, as it is called in the books, _Cebus capucinus_. As in the case of the two preceding species, it is an inhabitant of Venezuela and Brazil, and as lively as any of its congeners. Like its brethren, its tail is invested with a dense growth of hair, but this does not interfere with its prehensile powers. The Sai is possessed of a large amount of intelligence, and its quaint little ways make it a great favorite with those who delight to watch its quick and agile movements. While things of a vegetable character constitute the chief part of its food, yet it manifests a fondness for various kinds of insects, and is sometimes known to ascend to higher prey, for it has been observed to feed upon birds, which it devours with avidity, not even waiting to pluck off the feathers. Eggs are also thought to form a no inconsiderable part of this Capuchin’s diet. Some few years ago, Prof. Cope had in his possession a tame Sai, which was kept in a cage, or, rather, was supposed to be kept in it, for the animal had a strong aversion to confinement, and was sure to break loose therefrom sooner or later. When in durance vile, and wishing to break prison, he always directed his attention to the hinges, and no matter how firmly they were fixed, he was sure before long to extract the staples, pull out the nails, and so open the door at the hinges, and not at the latch.